Sealed systems that contain living organisms and utilize photons as an energy source to maintain the health of living organisms inside usually are called "closed ecological systems". While many simplified closed ecological systems exist, complex systems that remain in dynamic equilibrium over multiple generations of macro organisms exploiting closed-loop gas and nutrient cycles have been desired but were not attained until the present invention.
One advantage of a sealed environment with a complex ecosystem is that biogeochemical processes occurring within the system can be quantified and the genetic make up of the system can be controlled. Scientific study seeks to vary only one parameter at a time. Sealed ecological systems allow for such parameter control. For example, by the control of one parameter among many, the biogeochemical and ecosystem effects of the one variable can be studied. Studies can employ multiple sealed systems to analyze the impact of various parameters. For example, the effects of low level industrial pollution, or the fate of a new genetically-engineered organism in an ecosystem lend themselves to such study.
Previous to the invention described herein, short-term stability was obtained only in simple closed ecosystems that did not include plants and for only as long as the animals contained in the system survived. The animals were not reproducing. The lack of species diversity in these systems as well as the non-reproducing animals make these systems less desirable than the present invention for research purposes. The present invention provides a closed ecological system which remains in dynamic equilibrium, in which material cycles are closed, and which contains species from the kingdoms plantae, animalia or fungi that reproduce and sustain multiple generations.
Previous prior art attempts at creating a stable, complex, closed ecological system have met with limited success and have used the following three principles. First, enhance net primary production by providing a nutrient supply for photosynthetic organism that maintains a high rate of photosynthesis, which ensures adequate food and oxygen for organisms in the system. Second, enhance net primary production by providing a source of carbon for the photosynthetic organisms, maximizing plant production. Third, enhance system stability by providing separate compartments with controlled material exchange between compartments. The inventors of the present invention have found that individually, and in combination, the above three factors used in the prior art actually diminish the stability of a closed ecological system.
Closed ecological systems utilizing the three principles above have been available for years. Systems built by Dr. Claire Folsome of the University of Hawaii starting in the 1960s and the system marketed as the "Ecosphere" are microbially-based, and do not support breeding populations of plants and animals. Although these systems are closed ecosystems, they do not parallel the complex ecosystems found in the natural world. Additionally, because they do not include reproducing populations of plants and animals they are of limited value in research and education. The present invention allows much greater species richness and diversity, and allow all kingdoms of life to exist within a single, relatively small system.
Other ecosystems, designed for aesthetic and educational uses and commonly called vivariums, lack the ability to remain in dynamic equilibrium when sealed for extended periods of time. U.S. Pat. No. 4,122,800 to Mangarell 1978 4,958,593 to Hurlburt et al. 1990 5,328,049 to Ritzow 1994 5,183,004 to Trent et al. 1993 5,054,424 to Sy 1991 5,135,400 to Ramey 1992, and 4,117,805 to Ward 1978, are all variations of the vivarium concept. All of these are meant to be unsealed or never sealed in order to facilitate regular and scheduled cleaning and internal housekeeping of the plants, animal species and soil and/or water changes. Cleaning is necessary because the systems, as assembled, do not contain inherent controls on the proliferation of microbial life forms that will eventually dominate and destroy the life systems within. Thus dynamic equilibrium cannot be maintained in these prior art inventions. For example, Mangarell '800 describes a "self contained" system, but actually contains only the macro organisms, solids or liquid material. Atmospheric gases, particulates, microbial and/or viral life forms are not prevented from entering or exiting the system. These systems are also not transportable. The present invention allows for transportation for display and study.
Biological systems that filter or otherwise cleanse liquid and gas are commonplace. However, most, like U.S. Pat. No. 4,093,546 to Taborsky 1978 or U.S. Pat. No. 3,957,017 to Carmignani et al. 1976, use non-renewable filters to support the biological systems. Thus human intervention is required for maintenance or replacement using such systems. The present invention is self-sustaining and requires no maintenance.
The most ambitious closed ecological system in the prior art is that system known as "Biosphere 2," located in Oracle, Ariz. One patent is applicable to the invention described herein: U.S. Pat. No. 5,322,035 to Hawes et al. 1994, for a Hydrological System for a Closed Ecological System. While the Hawes discloses a hydrological cycle within a closed ecological system, an "ocean", a crabwalk, a desalination process, agricultural systems and particularly mechanical systems are required to maintain stability. Hawes does not provide for the transport of nutrients from one environment to another, with no balancing of nutrient production and uptake between species. Thus, the Hawes system is subject to imbalances which must be controlled by operator intervention. The present invention overcomes the prior art limitations, provides for nutrient transport and balancing without operator intervention. The present invention allows a sealed ecological system to remain in dynamic equilibrium without human intervention.